Electric switch



Feb. 21, 1950 M. B. COLE 2,493,531

ELECTRIC SWITCH Filed July 24, 1947 4 INVENTOR. MELVIN B. (01.5

Patented Feb. 21, 1950 mesne assignments, to Federal Electric Products- Company,yNewark, N.-J., a corporation of Delaware Application 51113724, 1947;"Serial No. 763,205

Claims. 1;

Thisinvention relates: to electric switches and more particularly to switchesiof the knife-blade type.

Switchesv having pivoted blade contact-imem-' bersare customarily providedwit-h spring means, associated with. the" pivoted blade. and-:with the pivot pin .by which said blade is pivotally connected to a stationary terminal-stud carried by. the insulation base of the switch. It will .be understood-that it is important that the blade contact. have a firm contact with the terminalstud in order toprovide a good electrical connection between said blade contact and the stud and that the spring means isprovided for that purpose;

In one well known switch construction of this type, the pivot pin is in the form of a rivet and the spring means isin the form of a cupped spring: member which is disposed between the head of the-rivetand the adjacent side of the contact blade, the shank of the rivet passing through an opening in the spring member'and through aligned openings in'the contact blade and: in the terminal-stud. That construction has been found to be'very' unsatisfactory because, among other things, the springpressure between the blade contact and the terminal-stud cannot be properly determined since the rivets which are supposed to be ofthe same size actually-are not uniformly of the same size, particularly-in respect to the lengths of their shanks. Due tothe' lack of uniformity in the size' of rivets or to non-uniform upsetting-of the free-ends of the rivets; the degreeof spring pressure varies in different switches.- In many instances,' such pressureis too low because of long rivet shanks and as a result the blade doesnothave. the necessary firm contact with" the stud for a good electrical connection; ,In other instances the-cupped spring may be deformed due to excessive shortening of the rivet shanks when the free ends thereof are upset, with the result'that the resiliency of the spring member is impaired or considerably reduced or even destroyed; sothatthe bladedoes not engage-the stud with a good electrical connection therebetweenand' this condition usually becomes worse after a period of use of the switch.

The primary object of the-present invention, therefore, is to obviate the above mentionedobjections and disadvantages and for that purpose to provide a switch of the blade-contact type with means for resiliently pressing the contact blade against the terminal-stud without interference by the rivet or other pivot pin by which the blade is pivotally connected to the stud.

Thetabove and otherobjects, features; and: ad vantages of the present invention-twill; be fully. understood from. the following descriptionxcone sidered in. connection with the accompanying. il-r. lustrative. drawings.

In the: drawings:

Fig. .1 is a perspective View of a switch embody.- ingthe present invention; r

Fig. 2 is a side View 'of'part..of.theswitch;1

Fig.3 is an end viewofa spring member-pros. vided in the switch;

Figml is asectional. view on thexzline-L-l 01 Fig. 2.

Referring: now to the drawings in detail, the switch embodying the present invention prises an insulation base l 0, a stationary: contact member l2, connected toa terminal member-A 3;, and a movable-*blade-contact member M which is-pivotally' connected to the-terminalsstudr-ISL Also, as-here shown the switch is customarily; but not necessarily;- provided with :fuse clips l 8 and 20 connected respectively 'to the: terminal member '22 and to the terminal stud- IS. The movab'l'e'blade-contact member 44 comprises the resilient m'et-a'lstrips 2 4 and" i 2 5 having interme diate portions-26 and- 28" which are' secured in face to face relation in any suitable-way,asaby' rivets 30.- The insulation -operating member .32

for moving the blade-contact member M -i'nto andout of engagement with the: companion station-" ary member- I2 is secured to said blade contact member 14 at said intermediate portions 26 and 28- in any suitable wayyusually as here shown by-the rivets 30. At the end of member M-which engages contact member l2, said member M has laterally spaced parts 34"and 36- between" which the-contact member I2 is received and which re-* siliently engage the opposite sides of said'contact member in the closed condition of the switch-r At the pivoted end of -the'movable contact member lithe-latter is similarly provided'with laterally spaced parts 31 and 38 which are disposedat' opposite'sid'es' respectively of the terminal-stud 1E. Saidterminal-stud I6 is provided'with an opening 40 and saidl'aterally spaced parts'3'l and'38 are providedwith openings 42and M respectively in registry with opening 49 0f stud l6. The-shank or stem 45 of the pivot pin 46 passes through "said" openings with slight clearance for pivotally con necting the movable contact member or blade M to said stud Hi. It will be noted that the pivot pin has a head 50 which, in the specific form of the invention illustrated herein, abuts the outer side of part 31 of the contact member, instead of being spaced from said part by the cupped 3 spring of the above mentioned known construction.

As hereinbefore indicated, the switch of the present invention includes resilient means for pressing the lateral parts 31 and 38 against the adjacent sides respectively of stud l6. As here shown said spring means is preferably constituted by a U-shaped spring member 52 which straddles parts 31 and 38 at the pivot pin it and which is secured to the movable contact member in that position. More specifically, as here shown spring member 52, which is formed in one piece of suitable spring steel, includes the spring arms 53 and 54 which resiliently engage the head 50 of the pin and the blade part 38, respectively. Arm 54 is provided with an opening 56 through which the outer end of the shank of the rivet or pivot pin 4% projects.

It will be noted that in the foregoing construction provided in accordance with the present invention, the spring member 52 presses the head 59 of the rivet against the part 31 of the blade I and thereby presses said part of the blade against the adjacent side surface of the stud l5.

Similarly, it will be noted that the spring arm 54 presses the other lateral part of the blade [4, namely part 38, against the other side surface of the terminal stud l6. Thus the resilient means, which is constituted by spring 52, presses parts 37 and 38 toward each other into resilient engagement with stud it. It will be readily understood that by reason of this construction the resilient pressure between the parts 37 and 38 and stud I6 is independent of the size of the rivet or pivot pin 46. Further, it will be noted that it is unnecessary to upset the end of the rivet shank or pivot pin, since the spring holds the rivet in position. This is an additional advantage of the present invention since the upsetting operation is eliminated. Moreover, this enables the blade contact I l to be removed and replaced quickly and with ease.

Arms 53 and 54 of spring member 52 preferably are provided with relatively diverging end portions 58 and 60 to facilitate the assembly of said spring member with the companion parts of the switch. For convenience of assembly an opening 56 is also provided in arm 53 so that the spring member can be attached with either arm thereof at the stem of the pivot pin. Further, as here shown end portions 58 and 60 are provided with grooves 62 and 64, respectively, each leading to the recess or opening 56 in the companion arm, thus additionally facilitating the assembly of the spring member.

Various changes in the details of construction and in the form and arrangement of parts may be made and,.similarly, the invention may be embodied in other switch constructions without departing from the underlying ideas or principles of the invention within the scope of the appended claims.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. In an electric switch which comprises a metal stud having an opening therethrough, and a movable switch-contact blade having laterally spaced parts disposed at opposite sides respectively of said stud and provided with openings registering with said opening of the stud, a pivot pin passing through all of said openings for pivotally securing said blade to said stud, said pin having a head engaging the outer surface of one of said parts and a stern projecting through said openings beyond the outer surface of the other of said parts, and spring means pressing said head against said one of said parts, and thereby pressing said one of said parts against the adjacent side of said stud, said spring means also pressing the other of said parts against the other side of said stud independently of said pin.

2. The switohdefined by claim 1 further characterized in that said spring means comprises a resilient U-shaped member which has spring arms respectively pressing resiliently against said head of the pin and the other of said parts.

3. The switch defined by claim 2, further characterized in that the spring arm which presses the other of said parts against the stud is provided with an opening through which the stem of said pin projects.

4. In an electric switch which comprises a metal stud having an opening therethrough, and a movable switch-contact blade having laterally spaced parts disposed at opposite sides respectively of said stud and provided with openings registering with said opening of the stud, a pivot pin passing through all of said openings for pivotally securing said blade to said stud, said pin having a head engaging the outer surface of one of said parts and a stem projecting through said openings beyond the outer surface of the other of said parts, a one-piece U-shaped spring straddling said spaced parts and the stud therebetween and resiliently pressing said spaced parts toward each other against said opposite sides, respectively, of said stud, one of the arms of said U-shaped spring pressing against the outer side of said head of the pivot pin and the other arm of said U-shaped spring pressing directly against the outer side of the other of said parts inde pendently of said pin.

5. In an electric switch which comprises a metal stud, a movable switch-contact blade, and a pivot pin for pivotally connecting said blade to said stud, the combination with the said stud, blade and pivot pin of a U-shaped spring straddling said stud and blade in the region of said pivot pin for resiliently pressing said blade against said stud, said pivot pin having a head and a stern, one of the arms of said U-shaped spring pressing against said head at the outer side thereof and the other arm of said spring having a recess in which said stem is received.

MELVIN B. COLE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,354,525 Trumbull et al Oct. 5, 1920 2,237,283 Baskerville et al. Apr. 8, 1941 FOREIGN PATENTS Number Country Date 100,382 Sweden Dec. 3, 1940 

